Monday, December 14, 2009

By tomorrow this time 7pm IST, we may not be able to see not even a single remnant of Cyclone "Ward" over Bay.
A weak circulation may emerge over Gulf of Mannar on evening of 15-Dec-09.

JTWC: warning
------------------
140900Z POSITION NEAR 8.8N 81.1E.
TROPICAL CYCLONE (TC) 05B (WARD), LOCATED APPROXIMATELY 140 NM
NORTHEAST OF COLOMBO, SRI LANKA, HAS TRACKED WEST-SOUTHWESTWARD
AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY INDICATES THAT THE LOW LEVEL CIRCULATION CENTER
(LLCC) HAS BECOME INCREASINGLY DISORGANIZED WITH BURSTS OF DEEP
CONVECTION EAST OF THE CENTER. A 140510Z TRMM 37V GHZ IMAGE SHOWS
THAT THE LLCC IS LOCATED ALONG THE EAST COAST OF SRI LANKA WITH
WEAKLY CURVED BANDING. THE CURRENT INTENSITY IS BASED ON DVORAK
ESTIMATES OF 30 KNOTS FROM PGTW, KNES, AND DEMS. TC 05B IS CURRENTLY
DRIFTING WEST-SOUTHWESTWARD AND IS EXPECTED TO CONTINUE TRACKING
ACROSS THE EAST COAST OF SRI LANKA, AND DISSIPATE WITHIN THE NEXT 12
HOURS. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON
WARNING CENTER (NAVMARFCSTCEN). THE SYSTEM WILL BE CLOSELY
MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 140600Z IS 10 FEET

The deep depression over southwest Bay of Bengal crossed north Sri Lanka coast near Trincomalee (Sri Lanka) between 1330 and 1430 hours IST of today, the 14th December 2009 and lay as a depression over north Sri Lanka near lat. 8.50 N and long. 81.00 E, close to Trincomalee at 1430 hrs IST. It is likely to move in a westerly direction, emerge into Gulf of Mannar and cross south Tamil Nadu coast between Kanyakumari and Pamban around afternoon of tomorrow, the 15th December, 2009.
Under its influence, rainfall at many places with isolated heavy to very heavy falls is likely over north coastal Tamilnadu and Puducherry during next 36 hours. Rainfall at many places with isolated heavy to very heavy falls is also likely over south coastal Tamil Nadu during next 24 hours. Rainfall at most places with scattered heavy to very heavy falls and isolated extremely heavy falls (≥ 25 cm) is also likely over south Tamil Nadu for the subsequent 48 hours.
Squally winds speed reaching 45-55 kmph gusting to 65 Kmph are likely along and off Tamil Nadu coast during next 36 hours . Sea condition will rough to very rough along and off Tamil Nadu and Puducherry coasts.

Tropical Cyclone Ward has spooked forecasts by real-time cyclone tracking models by changing course overnight on Sunday and heading west-southwest from its previous day's bearing over the southwest Bay of Bengal.

It has since ceased to become a tropical cyclone, having weakened a notch lower into a deep depression with further prospects of weakening before it encounters the north-eastern coast of Sri Lanka by Monday morning for the first landfall.

LANDFALL OVER TN
India Meteorological Department (IMD) and other real-time tracking models such as the US Navy's Joint Typhoon Warning Centre (JTWC) expect the weakened ‘Ward' to later emerge into the Gulf of Mannar and crawl into the south-east Tamil Nadu coast between Kanyakumari and Pamban for a second landfall by Tuesday morning.

In contrast, the cyclone phase evolution and tracking models that put out forecasts even weeks ahead had been suggesting the approach of a cyclonic circulation over Sri Lanka and its passage into the Gulf of Mannar for a second landfall over mainland India.

But on Sunday, these models seemed to rule out the possibility of the remnant of ‘Ward' making its way into mainland India (Kanyakumari-Pamban as suggested by IMD and others).

Instead, it would cross Sri Lanka with a west-southwest orientation and head into the adjacent equatorial Indian Ocean before getting dissipated. Only one model suggested the prospect of the system taking a re-curve from the Gulf of Mannar and heading back into the open waters of the Bay of Bengal skirting the Tamil Nadu coast.

Sea-surface temperature

An analysis of the meteorological parameters determining the course of ‘Ward' suggested that the sudden drop of sea-surface temperatures (SSTs) may have caused the system to decelerate and weaken overnight.

Sea-based weather systems have a penchant for seeking warmer waters and this is what ‘Ward' is doing by heading west-southwest into south-west Bay of Bengal and equatorial Indian Ocean surrounding central Sri Lanka.

The Gulf of Mannar happens to be cooler, and if the ‘Ward' remnant were to enter these waters as forecast by the other agencies, it would lead to further weakening of the system en route to Kanyakumari-Pamban.

In its update on Sunday evening, the IMD said that the deep depression over south-west Bay of Bengal slightly moved southward and lay centred about 200 km east-northeast of Trincomalee (Sri Lanka), 400 km southeast of Nagapattinam and 400 km east of Pamban.

The Chennai Met Centre said in its update that the cyclonic storm had helped launch the north-east monsoon back into a vigorous phase over coastal Tamil Nadu.

Rainfall occurred at many places over coastal Tamil Nadu and at a few places over interior Tamil Nadu. Isolated rainfall occurred over coastal Andhra Pradesh and Rayalaseema.

Forecast for the next two days said that rain or thundershowers are likely at most places over coastal Tamil Nadu and Puducherry; at many places over interior Tamil Nadu andat a few places over south coastal Andhra Pradesh, Rayalaseema, Kerala and Lakshadweep.

Isolated rain or thundershowers are likely to occur over north coastal Andhra Pradesh, coastal and south interior Karnataka.

An IMD warning has said that squally winds with speed reaching 55 to 65 km/hr gusting to 75 km/hr are likely along and off the south Tamil Nadu coast during next two days.

Squally winds with speed reaching 50 to 60 km/hr gusting to 70 km/hr is likely along and off north Tamil Nadu and Puducherry coast during the next 24 hours.

Sea condition will be very rough to high along and off south Tamil Nadu coast and very rough along and off north Tamil Nadu and Puducherry coasts.

International models suggested that another wave of disturbed weather would descend over south-east and adjoining south-west Bay of Bengal from December 21 onwards.

Cyclone "ward" overnight slowly moved to west and dissipated.
now 8:30am IST, it's very close to north-east tip of Srilanka.
There's a chance that it'll skirt the northern tip of srilanka and make a landfall along the central Tamilnadu coast in another 24hrs as just a LOW pressure system.
There's a 95% chance that this system will cause very heavy showers along the central, and south-east coast of Tamilnadu in another 24hrs.
Under this influence the North-East monsoon current will be active all along the Tamilnadu coast.
Heavy to moderate showers possible along the coast and over some parts of interior Tamilnadu.

Satellite shot at 7:30 am IST
--------------------------------

JTWC: warning 5:30 am IST
---------------------------
140300Z POSITION NEAR 8.9N 81.4E.
TROPICAL CYCLONE (TC) 05B (WARD), LOCATED APPROXIMATELY 160 NM NORTH-
EAST OF COLOMBO, SRI LANKA, HAS TRACKED WESTWARD AT 04 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS THAT THE
LOW LEVEL CIRCULATION CENTER (LLCC) HAS STARTED TO WEAKEN AS IT
SLOWLY TRACKS TO THE WEST. CONVECTION IS SPORADICALLY DEVELOPING AND
DISSIPATING OVER THE PAST SIX HOURS. CURRENT FORECAST HAS THE SYSTEM
MOVING TOWARDS SRI LANKA AND MAKE LANDFALL WITHIN THE NEXT 6 TO 12
HOURS. FURTHER WEAKENING IS EXPECTED UPON MAKING LANDFALL WITH SRI
LANKA. ONCE THE LLCC MOVES BACK OVER WATER, AROUND TAU 24, THERE IS
NOT EXPECTED TO BE ANY ADDITIONAL DEVELOPMENT. COMPLETE DISSIPATION
IS EXPECTED AS TC 05B MAKES LANDFALL IN SOUTHERN INDIA. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 140000Z IS 11 FEET.

The deep depression over southwest Bay of Bengal moved westwards and lay centred at 2330 hours IST of yesterday, 13th December 2009 near lat. 9.00 N and long. 82.50 E, about 130 km east-northeast of Trincomalee (Sri Lanka), 330 km southeast of Nagapattinam and 350 km east of Pamban. The system is likely to move in a westerly direction and cross north Sri Lanka near Lat. 9.00 N around noon of today, the 14th December, 2009. Subsequently, it is likely to move in a west-southwesterly direction, emerge into Gulf of Mannar and cross south Tamil Nadu coast between Kanyakumari and Pamban around afternoon of tomorrow, the 15th December, 2009.